As an active wiring line device by a technique of forming a transistor in a wiring layer, a CMOS (Complementary Metal Oxide The semiconductor) inverter is sometimes formed. By using the CMOS inverter, a pass-through current can be restrained and power saving can be achieved, compared with a case where only a NMOS transistor or a PMOS transistor is used. In order to realize the CMOS inverter, a p-type metal oxide transistor is required in addition to an n-type metal oxide transistor. Also, it is desirable that the process in which they are formed does not have an influence on a wiring layer.
In relation to the p-type metal oxide transistor, Patent Literature 1 and Non-Patent Literature 1 discloses a transistor which has a tin oxide (SnO) film formed on an YSZ substrate by an epitaxial growth method in a channel layer. Also, Non-Patent Literature 2 discloses a technique of forming a polycrystalline SnO film on a SiO2 substrate by a sputtering method, to use it as a channel. In addition, it discloses a technique of obtaining a polycrystalline SnO film by carrying out post-deposition anneal (PDA).
On the other hand, as for the structure of a transistor, a semiconductor device is disclosed in Patent Literature 2. The semiconductor device includes a semiconductor substrate; an insulating layer formed on the semiconductor substrate; a first wiring layer having a first wiring line embedded in a surface portion of the insulating layer; a semiconductor layer provided on the first wiring layer; a gate insulating film provided on or under the semiconductor layer; and a gate electrode provided to oppose to the semiconductor layer through the gate insulating film.